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Felix SeipFS

Felix Seip

Full Stack Developer

€720/day
Frankfurt am Main, DE
8-15 years

Average response time: 1 hour

About Felix

Need to move faster, but your team’s already at capacity?

I help product teams and tech leaders deliver backend-heavy features, integrations, and infrastructure - fast, clean, and in 2-week fixed-scope sprints.

Whether you’re unblocking a roadmap item, integrating third-party systems, or building internal tools, I bring clarity, speed, and production-ready code.

With 9+ years of experience in Java, Spring Boot, AWS, and modern frontend frameworks (React, Next.js, Tailwind), I plug into teams quickly and deliver with minimal overhead.
- Backend systems & APIs (Spring Boot, PostgreSQL, microservices)
- Fullstack feature delivery (React, Tailwind, etc.)
- AWS infrastructure (ECS, Lambda, CDK, Terraform)
- AI integrations (LLMs, GPT APIs, RAG pipelines)
- ETL automation, dashboards, platform APIs (Salesforce, SAP, etc.)

Teams at TUI, BMW, ING, and several startups trust me to deliver - hands-on, architectural, and outcome-driven.

📍 Based in Frankfurt · Remote-friendly · English & German
  • English

    Native or bilingual

  • German

    Native or bilingual

Can work on-site
Frankfurt am Main (up to 15km)

Experience

  • Micromerce
    Senior Software Engineer
    May 2024 - Today (2 years and 2 months)
    • Developed complex customer workflows on the Micromerce platform to streamline business operations.
    • Co-developed a support tool using RAG and LLMs for automated responses, improving support efficiency.
    • Processed Salesforce data for actionable insights, set up automated dashboards for KPI tracking, and prepared C-level reports to support strategic decision-making.
    • Leading outsourcing initiatives and managing external development teams to ensure delivery quality, scalability, and cost-efficiency.
    • Coaching & mentoring of 4 junior colleagues
  • Self-employed
    Freelance Full Stack Software Engineer
    December 2021 - October 2024 (2 years and 10 months)
    • Mentored a junior developer in Clean Code, architecture understanding, and TDD strategies.
    • Collaborated closely with business units to implement complex requirements in existing systems.
    • Advised on Microservices architecture, API design, and communication using SQS/SNS.
    • Developed automated ETL pipelines and tools for data extraction and conversion.
  • ING Deutschland
    Application Developer
    February 2020 - December 2021 (1 year and 10 months)
    Frankfurt, HE, Germany
    Delivered and tested regulatory banking features in a complex Java/Spring Boot microservices landscape with a focus on quality and maintainability.
    • Developed Test Reporting Hub application for automated archiving of test results meeting ECB regulatory requirements.
    • Enhanced FitNesse Central test wiki system for efficient test case validation against applications.
    • Created Test Reporting Maven Plugin for seamless integration into Jenkins pipelines for automated test reporting.

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Education

  • Mathematisch-technische/r Softwareentwickler, Mathematics and Computer Science
    Oberstufenzentrum für Informations- und Medizintechnik Berlin
    2018
    Mathematisch-technische/r Softwareentwickler, Mathematics and Computer Science
  • High School Diploma
    Trumbull High School
    2015
    High School Diploma

Skill set

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